Effect Of Doping On Corrosion Resistance Property And Wear Resistance Property And Thermal Conductivity Of FeCoCrMoCBY BMGs

In this paper,(Fe₄₁Co₇Cr₁₅Mo₁₄C₁₅B₆Y₂)_100-xCrx?x=0, 4, 8, 12 at%, BMG1,BMG2,BMG3,BMG4? and(Fe₄₁Co₇Cr₁₅Mo₁₄C₁₅B₆Y₂)_100-x(Co₆₅Cr₁₅Zr₁₀W₁₀)x?x=5,10, 15 at%, BMG5, BMG6,BMG7? bulk amorphous alloys were fabricated using the non-consumable type vacuum arc melting furnace water-cooled copper mold suction casting method. The structure and the corrosion resistance of the alloys were characterized using X-ray diffraction?XRD? and electrochemical workstation,respectively. The thermodynamic parameters of amorphous alloy have been got by differential thermal analysis?DSC?, laser flash thermal conductivity tester and four probe resistance tester, respectively. The wear resistance performance and wear mechanism of the alloys were measured by WTM-2E friction and wear tester. The surface morphology after corrosion and wear and the content of element and the composition of the passive film were analyzed by X-ray photoelectron spectroscopy?XPS?, scanning electron microscopy?SEM? and elements energy spectrum analysis?EDS?, respectively. This article focus on the effects of Cr element and Co₆₅Cr₁₅Zr₁₀W₁₀ amorphous alloy doping on the corrosion resistance of Fe-based bulk amorphous alloy in 3%NaCl, 1mol/L HCl and 1mol/L NaOH. To explore the optimal Cr/Mo ratio in the FeCoCrMoCBY amorphous alloys, and the optimum doping content of Co₆₅Cr₁₅Zr₁₀W₁₀ amorphous alloy, and the effects of Cr element and Co₆₅Cr₁₅Zr₁₀W₁₀ amorphous alloy doping on the thermal conductivity and wear resistance of Fe-based bulk amorphous alloy. The relationship between hardness,crystallization temperature?Tx? and thermal conductivity is established.Through the polarization curves and EIS, it was found that the corrosion resistance of Fe-based bulk amorphous alloy was improved by the doping of Cr element and Co₆₅Cr₁₅Zr₁₀W₁₀ amorphous alloy. The corrosion resistance of Fe-based bulk amorphous alloys is the best in the Fe CoCrMoCBY amorphous alloy system when the Cr/Mo ratio is in the range of 1.37¹.69. The best doping amount of Co₆₅Cr₁₅Zr₁₀W₁₀ is 5at%, which can improve the corrosion resistance and economic benefits. Through the analysis of the M-S curve of the passive film of BMG2, BMG3 and BMG4 in 1mol/L HCl, and BMG5, BMG6 and BMG7 in 3% NaCl, it is found that the stability of the passive film of the alloy and the protection of the substrate are better when the Cr/Mo ratio is 1.37¹.69 and Co₆₅Cr₁₅Zr₁₀W₁₀ is 15at%.Through the analysis of the passive film composition of BMG2, BMG3 andBMG4 in 1mol/L HCl, it can be obtained that the stability of passive film is determined by the synergistic action of Cr and Mo elements, the main component of the passive film is Cr3+ oxide or hydroxides. When the potential is lower than 0.5VSCE,Cr3+ state is main ion to determine the corrosion resistance, but when the potential is higher than 0.5VSCE, Mo6+state is the main component that determines the stability of the passive film. The surface morphology and composition analysis of BMG5, BMG6 and BMG7 after 336 h immersion in saturated NaCl solution showed that the more amount of Co₆₅Cr₁₅Zr₁₀W₁₀ doped, the smaller the number and the diameter of the pit.The reason for the improvement of corrosion resistance is not the introduction of Zr,but the doping of Co₆₅Cr₁₅Zr₁₀W₁₀ amorphous alloy leads to more Cr enrichment on the surface, forming a more dense passive film. Compared with the change of the internal structure of the alloy, the influence of alloy composition on corrosion resistance is greater.The wear resistance of Fe-based bulk amorphous alloys increased with the increase of the content of Cr, the reason for the improvement of the wear resistance is the disappearance of abrasive wear, leaving only the fatigue wear. With the increase of Co₆₅Cr₁₅Zr₁₀W₁₀ doping content, the wear coefficient decreases firstly and then increases. The main reason is that the main wear mechanism is changed to adhesive wear. There is a good linear relationship between hardness and Tx, Y=3.28X-790.62.The doping of Cr leads to the increase of the electrical resistivity, while the effect on the thermal conductivity is small, and the thermal conductivity and the electrical resistivity of Fe-based bulk amorphous alloy are decreased by doping Co₆₅Cr₁₅Zr₁₀W₁₀ alloy. In the range of 25 to 150 ?, the thermal conductivity of Fe-based bulk amorphous alloy increases linearly with the increase of temperature.Doping mainly results in the change of phonon thermal conductivity at room temperature, and the effect of doping on the electron thermal conductivity is very small. A formula for calculating the thermal conductivity of Fe-based bulk amorphous alloy at room temperature is presented by using Tx, the relationship between phonon thermal conductivity and Tx is in line with Y=0.06756X-37.31568, the relationship between total thermal conductivity and hardness is in line with Y=0.01833X-30.58814. Therefore, the relationship between total thermal conductivity and Tx is in line with Y=0.06228X-14.83836.